1. Technical Field
This invention generally relates to image forming apparatuses such as digital copying machines with electrophotographic systems, laser printers, and the like.
2. Related Art
In image forming apparatuses that employ electrophotographic systems, in general, a light emitted from an optical scanning device composed of: a light source such as a semiconductor laser; and various optical parts is exposed to a photosensitive drum serving as an image holding body uniformly charged to form a latent image. Then, the latent image is developed with toner. Such developed toner image is transferred to a recording medium.
In the above-described image forming apparatus, when the toner or dusts are adhered to various optical parts included in the optical scanning device, high image quality cannot be maintained. For this reason, there is known a configuration in which the optical parts included in the optical scanning device are accommodated in a hermetically sealed chassis and the photosensitive drum is exposed to a light through a seal glass (light transmitting portion) arranged at the chassis. There is known another configuration in which the seal glass is provided at a chassis of an optical scanning unit is provided with a cleaning mechanism that removes the toner or ducts adhered to the surface of the seal glass. In the above-described cleaning mechanism, the surface of the seal glass is cleaned by sliding a pad provided at an end of a cleaning rod, when the cleaning rod is inserted or pulled out.